JP3546575B2 - Material testing machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a material testing machine, and more particularly, to a mechanism for clamping a crosshead to a column by frictional force.
[0002]
[Prior art]
Conventionally, as shown in FIGS. 3 and 4, a pair of columns 2 are erected on a table 101, and a crosshead 1 is provided above the columns 2 so as to be able to move up and down. Accordingly, the crosshead 1 is raised and lowered along the column 2 and fixed, and a test piece is attached to the gripper 102 provided on the crosshead 1 and the gripper 103 provided on the driving means 104 side, and one of the grippers 103 is attached. It is moved by the driving means 104 to perform a tensile test or the like.
[0003]
In such a testing machine, it is necessary to clamp the crosshead 1 and the column 2 penetrating the crosshead 1, and as shown in FIG. Split grooves 4 are formed in the portions 3A and 3B, the split grooves 4 are elastically deformed and clamped by a clamp mechanism 6 using a flat hydraulic cylinder 5, and the gap between the crosshead 1 and the support column 2 is narrowed and clamped. I have.
[0004]
As shown in FIG. 5, such a clamping mechanism 6 includes a hydraulic cylinder 5 having a ram 5A fixed to the crosshead 1 and a cylinder portion 5B sliding along the outer peripheral surface of the ram 5A, 5, a bolt member 8 having a locking head 8A penetrating through the mounting hole 7 and being locked to the cylinder portion 5B, and a lock nut 9 screwed to the tip of the bolt member 8. If pressure oil is supplied between the ram 5A and the cylinder portion 5B, the split groove 4 of the crosshead 1 is elastically deformed and narrowed by the ram 5A and the lock nut 9, and the gap between the crosshead 1 and the support column 2 is reduced. When jammed, the crosshead 1 is clamped to the column 2. When the pressure oil is released, the elastic deformation of the split groove 4 returns, so that the clamp is released and the crosshead 1 can be raised and lowered freely.
[0005]
[Problems to be solved by the invention]
However, if the clamp is continued for a long time, the split groove 4 portion of the crosshead 1 is plastically deformed, so that even if an attempt is made to release the clamp by removing the pressurized oil, a gap cannot be formed between the crosshead 1 and the column 2. Then, the crosshead 1 remains fixed to the column 2, and the crosshead 1 cannot be moved up and down. Even if plastic deformation has not occurred in the initial stage of use, plastic deformation of the split groove 4 may occur due to long-term use, and it may be difficult to release the clamp.
[0006]
An object of the present invention is to solve such a problem and to forcibly release the crosshead 1 clamped to the support column 2.
[0007]
[Means for Solving the Problems]
The present invention provides a crosshead that moves up and down along a column, a clamp unit that fills a gap between the column and the crosshead, and fixes the column to the column by friction.When the fixing by the clamp unit is released, the crosshead and the column This is a material testing machine that eliminates the inconvenience of long-time clamping by providing a release mechanism that forcibly opens a gap between the two. The release mechanism uses an elastic force of a spring or the like, and is always urged to the crosshead by adjustment in a direction to open a gap between the crosshead and the support. It has a jack mechanism that can change the length of the mechanism.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 are diagrams showing a schematic configuration of a crosshead of a material testing machine according to an embodiment of the present invention. FIG. 1 is a cross-sectional view of the crosshead, and FIG. It is the side view seen. The material testing machine main body to which the crosshead of the present invention is attached is the same as that shown in FIG. 4 except for the crosshead, and the material testing machine shown in FIG. 1 and FIG. The crosshead will be described.
[0009]
The crosshead 1 shown in FIG. 1 protrudes out of the support column 2, and a split groove 4 is formed in the projecting portion 3, and a hydraulic cylinder is provided on the crosshead 1 so as to reduce the interval between the split grooves 4. 5 is provided.
[0010]
The clamp mechanism 6 penetrates a hydraulic cylinder 5 having a ram 5A fixed to the crosshead 1 and a cylinder portion 5B sliding along the outer peripheral surface of the ram 5A, and the hydraulic cylinder 5 and the mounting hole 7, A bolt member 8 having a locking head 8A locked to the cylinder portion 5B, and a lock nut 9 screwed to the tip of the bolt member 8 are provided. When pressure oil is supplied between the ram 5A and the cylinder portion 5B, the ram 5A attempts to approach the lock nut 9, so that the split groove of the crosshead 1 is elastically deformed and the interval therebetween is narrowed, and the crosshead is narrowed. The gap between the column 1 and the column 2 is closed, and the crosshead 1 is clamped to the column 2.
[0011]
On the other hand, when the clamp of the cross head 1 on the support 2 is released by the elasticity of the split groove 4 returning to the tip 3a of the protrusion 3, the release of the elastic force of the spring 11 is promoted. A used release mechanism 10 is provided. In the present embodiment, eight springs 11 are used, but the number is not limited to this. Further, in the present embodiment, the helical spring is used, but other springs such as a coil spring and a leaf spring may be used.
[0012]
The jack holder 12 in which the flat spring 11 is accommodated is fixed to the tip 3a by a bolt 13. A spring receiver 16 that is in contact with the protruding portion 3B is fitted into the inner diameter of the one-sided spring 11, and a bolt annier 14 is fitted into the inner diameter of the other-sided spring 11. A jack bolt 15 is screwed into the bolt annier 14, and a head 15A of the jack bolt 15 is brought into contact with the protrusion 3A. Since the jack bolt 15 is screwed into the bolt annier 14, the jack bolt 15 can be moved forward and backward with respect to the bolt annier 14 by rotating the jack bolt 15 with a spanner or the like. Therefore, it is possible to adjust the position of the head 15A in accordance with the interval between the split grooves 4 so that the elastic force of the flat spring 14 is always urged in the direction of expanding the interval between the split grooves 4.
[0013]
As shown in FIG. 2, the release mechanisms 10 are provided at three positions in the vertical direction of the tip 3a of the crosshead 1, but the number is not limited to this.
[0014]
Next, the operation of the crosshead of FIG. 1 will be described. When mounting the test piece on the upper and lower grips 102 and 103, the crosshead 1 is moved up and down and positioned according to the length of the test piece. Then, pressure oil is injected into the cylinder portion 5B from a hydraulic source (not shown) so as to fix the positioned crosshead 1 to the column 2. Since the ram 5A moves in the direction approaching the lock nut 9 with the injection of the pressurized oil, the split groove 4 of the crosshead is elastically deformed, and the interval between the split grooves 4 is reduced, so that the crosshead The gap between 1 and the support 2 is blocked. In this way, the crosshead 1 is clamped on the column 2. This clamping force is greater than the force by which the parallel spring 11 attempts to widen the interval between the split grooves 4, and does not interfere with the clamp of the crosshead 1.
[0015]
After the crosshead 1 is clamped at a desired position in this manner, the test piece is mounted on the upper and lower grips 102 and 103, and a predetermined material test such as a tensile test is performed. After the test is completed, for example, when performing another test, when the length of the test piece is changed and the position of the crosshead 1 is changed, it is necessary to release the crosshead 1 clamped on the column 2.
[0016]
At this time, the hydraulic pressure source is controlled so as to discharge the pressure oil injected into the cylinder 5B. Soon, as the pressure oil is discharged, the crosshead 1 itself tries to return to the elastic deformation, and the spring 11 of the release mechanism 10 provided at the tip 3a of the crosshead 1 expands the space between the split grooves 4. As a result, a gap is again formed between the crosshead 1 and the column 2, the crosshead 1 is released from the clamp on the column 2, and the crosshead 1 can move up and down with respect to the column 2. As described above, since the release of the clamp is promoted by the release mechanism 10, the clamp due to the plastic deformation of the crosshead 1 does not remain, and the clamp is quickly released.
[0017]
Then, the crosshead 1 is positioned according to the length of the test piece to be tested next, clamped to the support 2 in the same manner as described above, and the test is repeated.
[0018]
Note that even if the split groove 4 of the crosshead 1 is plastically deformed due to long-term use and the interval changes, the jack bolt 15 is screwed into the bolt annier 14 and rotated with a spanner or the like. Accordingly, the head 15A can be advanced and retracted with respect to the bolt annier 14, and the elastic force of the flat spring 11 is always urged in the direction of expanding the interval between the split grooves 4, so that the head 15A is moved in accordance with the interval between the split grooves 4. It is possible to adjust the position.
[0019]
Further, even when the flat spring 11 is deformed and the predetermined elastic force is lost, the bolt 13 can be removed and the jack holder 12 can be removed, so that the flat spring 11 can be easily replaced.
[0020]
Further, in this embodiment, the hydraulic pressure of the hydraulic cylinder having the cylinder portion and the ram is used as the clamping means, but an air cylinder may be used.
[0021]
In addition, the following aspects are also included as modifications of the present invention.
[0022]
(1) A crosshead that moves up and down along a column, and a clamp that fills a gap between the column and the crosshead with hydraulic pressure of a hydraulic cylinder having a cylinder portion and a ram, and fixes the crosshead to the column by friction. And a release mechanism for forcibly opening a gap between the crosshead and the support when the fixing by the clamping means is released.
[0023]
【The invention's effect】
According to the present invention, when the clamp is released by removing the pressurized oil, the crosshead itself attempts to return to the original elastic deformation, and the release mechanism provided in the split groove portion increases the interval between the split grooves. Therefore, the plastic deformation of the split groove portion of the crosshead does not remain, the clamp is quickly released, and the crosshead can be moved up and down. In addition, the clamp is released immediately when the clamp is released because the release mechanism is always urged against the split groove so as to widen the interval between the split grooves even in the case of plastic deformation of the split groove portion due to long-term use. In addition, the release mechanism has a jack mechanism that can change the length, so it can respond to changes in the spacing of the split grooves, and even if the elasticity of the release mechanism is lost, the gap between the split grooves can be expanded. Can be.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a crosshead of a material testing machine according to one embodiment of the present invention.
FIG. 2 is a diagram showing a schematic configuration of the crosshead of FIG. 1 as viewed from the side.
FIG. 3 is a diagram showing a schematic configuration (plane) of a conventional material testing machine.
FIG. 4 is a diagram showing a schematic configuration (front view) of a conventional material testing machine.
FIG. 5 is a diagram showing a schematic configuration of a crosshead of a conventional material testing machine.
[Explanation of symbols]
1 Crosshead 2 Support 5 Hydraulic cylinder 6 Clamp mechanism 10 Release mechanism

Claims (1)

In a material testing machine comprising: a crosshead that moves up and down along a support, and a clamp that fills a gap between the support and the crosshead and fixes the crosshead to the support by friction. When released, a release mechanism for forcibly opening a gap between the crosshead and the support is provided. And material testing machine.

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